The present invention relates to a method of manufacturing rotationally symmetrical, particularly liquid-cooled, constructional parts, such as nozzles and combustion chambers of rocket engines, having their walls formed of wires or tubes abutting in juxtaposition and connected to each other, and spirally wound about the axis of symmetry of the constructional part.
In rocket construction, it is well-known to assemble liquid-cooled combustion chambers and thrust nozzles of tubes which are juxtaposed in the circumferential direction and firmly connected to each other. In such cases, because of the cross-sectional variation of the thrust nozzles and sometimes also the combustion chambers, the tube extent in the longitudinal direction must either be made with a cross-section varying in accordance with the respective variation of the diameter or, with a uniform cross-section of the tubes, the formed interspaces must be bridged by webs or filling material. In high pressure combustion chambers, for reasons of resistance, either pressure resistant external jackets or bandages are necessary. However, a multilayer wall structure of different materials may cause undesirable thermal stresses. On the other hand, the manufacture of tubes with necessarily largely varying cross-sections is complicated and expensive.
British Pat. No. 794,660 discloses a combustion chamber with a thrust nozzle having its walls enitely made of tubes which are juxtaposed in the circumferential direction and extend in spirals from one end of the constructional part to the other, with the pitch of each spiral depending on the respective diameter, i.e., being flatter for a larger diameter and steeper for a smaller diameter. The combustion chamber, as a constructional unit, is manufactured so that the individual tubes are bent to the necessary spiral shapes, juxtaposed individually or by twos and united by welding or another fastening method. Nothing is disclosed in this British patent, however, about the practical carrying out of the proposed method and the individual operational steps of their sequence.